And if you do need to drive it anywhere without a clutch:
Put it in gear
Start it (in gear)
Accelerate then hold a steady speed
Pull it out of gear, keeping the accelerator where it is (engine revs high)
Hold gear lever against the next gear (gently)
Release the acelerator
As the engine revs die down, they will slow down the cogs in the gearbox that are attached to the engine side of the drive train. When the speeds of the cogs are matched with the speed of the cogs attached to the wheels side of the drive train, the car will slip into gear
The process for going down the box is the same, except you need to rev the engine higher (past the speed of sync for the new lower gear)
e.g. If your car will drive along at 30mph doing 2500rpm in 3rd and 1500rpm in 4th, and youre currently doing 30mph@ 2500rpm in 3rd, you pull it out of 3rd, hold it against 4th, then let the revs die, and it will change into 4th as the revs pass 1500 rpm. If you miss, rev up and try again. To go back to 3rd, into neutral, rev up to 3000, hold against 3rd and let the revs die; it'll slot in at around 2500rpm
I'd only recommend this as a get-home measure of course, as replacing knackered syncro clutches is pricier than a clutch but my mother had a boyfriend a few years ago who drove his car for several months like this to no significant detriment.. He'd gotten it down to such a fine art, it took her a few weeks to realise he was never moving his clutch foot to change gear